1. Field of the Invention
This specification relates to a relay for an electric vehicle, and particularly, to a relay for an electric vehicle capable of opening or closing an electric power supply circuit installed at an electric vehicle and connected to a motor.
2. Background of the Invention
An electric vehicle may include a battery-only electric vehicle using only power charged at a battery, a hybrid vehicle using an electric power charged at a battery and/or a fossil fuel, a fuel cell vehicle, an electric golf cart and an electric fork lift. A relay for the electric vehicle is installed between a battery and an inverter, and serves to supply the electric power from the battery to the inverter, or to break the electric power supply to the inverter from the battery. Here, the inverter is a means to convert a direct current (DC) of the battery into an alternating current (AC), and to supply the converted AC to an AC motor configured to drive a vehicle.
The relay for an electric vehicle largely comprises a fixed contact, a movable contact movable to contact or be separated from the fixed contact, and an actuator for diving the movable contact. The fixed contact and the movable contact are accommodated in an arc extinguishing chamber. The arc extinguishing chamber is formed in an assembly implemented as an upside down cup-shaped ceramic cover is coupled to a supporting plate formed of a metallic material. The arc extinguishing chamber is sealed after extinguishing gas is filled therein, the extinguishing gas for extinguishing an arc generated when the fixed contact and the movable contact are separated from each other. The fixed contact is installation-supported at the ceramic cover, and the actuator is installation-supported at the supporting plate.
A metal connecting member is attached to an end of the ceramic cover. As the metal connecting member is adhered to the supporting plate by welding, implemented is an assembly of the air sealed-ceramic cover and the supporting plate.
In the conventional art, when the supporting plate and the metal connecting member are adhered to each other by welding for an assembly of the ceramic cover and the supporting plate to each other, a welding jig is used to fix the ceramic cover to a precise position.
However, the conventional relay for an electric vehicle may have the following disadvantages.
In a process of precisely positioning the metal connecting member coupled to the ceramic cover onto the supporting plate and then fixing them to each other by the welding jig, the assembly of the ceramic cover and the metal connecting member may be mal-aligned on the supporting plate with rotation. The reason is because the assembly is positioned on a flat upper surface of the supporting plate so as to be freely movable. That is, it is difficult to precisely align the assembly of the ceramic cover and the metal connecting member on the supporting plate when fixing the assembly onto the supporting plate by welding. Furthermore, when the assembly is fixed onto the supporting plate by welding at an imprecise position due to rotation, not a precise position, a welding quality may be degraded, and a horizontal position deviation may occur between the fixed contact and the movable contact. This may cause the occurrence of inferiority when the movable contact comes in contact with the fixed contact, and may lower the reliability of the relay for an electric vehicle.